<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8">
  <title>Document</title>
  <script src="jquery-3.6.0.min.js"></script>
</head>
<body>
  <div>
    <p class="fir">我是p标签</p>
    <div class="sec">我是div标签</div>
  </div>
  <script>
    $('.fir').clone().appendTo('.sec');
  </script>
</body>
</html>